JP6274220B2 - Wireless communication method and wireless communication device - Google Patents

Description

  The present disclosure relates generally to the field of wireless communication, and more particularly to a wireless communication method and a wireless communication device used in a cooperative multipoint communication system.

  A long term evolution (LTE) system is a frequency division system that uses orthogonal frequency division multiplexing (OFDM) as a reference multi-address multiplexing scheme. In this system, since the inside of the cell is completely frequency division orthogonal, there is almost no interference problem. However, since the interference at the cell edge is severe, the frequency spectrum efficiency at the cell edge has attracted attention. Currently, there are mainly three methods for processing interference at the cell edge in LTE: interference random, interference cancellation, and interference coordination (avoidance). In addition, interference cooperation can be easily realized, can be applied to various frequency widths, and has a good effect on interference suppression. Therefore, it is a technique often used for interference suppression between cells.

  For interference coordination, currently, frequency multiplexing schemes such as partial frequency multiplexing and soft frequency multiplexing are generally employed, and an obvious effect is achieved in suppressing interference at the same frequency between cell edge users.

  Due to the shortage of frequency spectrum resources and the current QoS needs of users, LTE-A, which is an advanced LTE, submits higher requirements for cell average frequency spectrum efficiency and cell edge frequency spectrum efficiency. In the future, it is preferable that the wireless communication system realizes full-frequency multiplexing while further improving the edge user performance so that high cell average frequency spectrum efficiency can be obtained simultaneously. Note that an enhanced physical downlink control channel (ePDCCH) is introduced in LTE-A, that is, it is allowed to transmit ePDCCH using a part of resources in the conventional physical downlink shared channel (PDSCH).

  With the introduction of ePDCCH, interference between edge users must be further reduced. However, since the edge multiplexing factor of partial frequency multiplexing is 3, the average frequency spectrum efficiency of the cell is greatly reduced. On the other hand, the performance of soft frequency multiplexing greatly decreases as the system load increases. Accordingly, the conventional interference coordination technology using frequency multiplexing cannot satisfy the current needs, and it is preferable to submit a new interference coordination proposal.

  The present invention is applied to a cooperative multipoint communication system so that full frequency multiplexing can be realized while improving edge user performance by further reducing interference between edge users in an LTE-A system in which ePDCCH is introduced. A wireless communication method and a wireless communication device used for ePDCCH interference coordination are provided.

According to one aspect of the present invention, there is provided a wireless communication method used in a cooperative multipoint communication system, which identifies an edge user device, determines the presence of interference on the ePDCCH of the edge user device, and determines the presence of interference. In response, a wireless communication method is provided that includes determining different interference coordination schemes according to different relationships between mutually interfering channels to control transmission of ePDCCH or PDSCH of neighboring cells for interference.

According to another aspect of the present invention, a wireless communication device used in a cooperative multipoint communication system, an identification unit for identifying an edge user device, and an interference determination unit for determining the presence of interference on the ePDCCH of the edge user device And an interference coordination unit that controls transmission of ePDCCH or PDSCH of neighboring cells related to interference by determining different interference coordination schemes according to different relationships between channels interfering with each other in response to determining the presence of interference. A wireless communication device is provided.

  By using the wireless communication method and wireless communication device according to the present disclosure, ePDCCH interference between edge users is reduced, accuracy of edge user reception control information is ensured, and cell edge user frequency spectrum efficiency is improved well. High cell average frequency spectrum efficiency can be ensured.

  It should be understood that both the above general description and the following detailed description are exemplary and explanatory and are not intended to limit the invention being protected.

  The foregoing and other objects, features and advantages of the present invention will become more apparent by referring to the description of embodiments of the present invention in conjunction with the accompanying drawings. In the accompanying drawings, the same or corresponding technical features or parts are denoted by the same or corresponding reference numerals. The accompanying drawings do not have to indicate the size and relative position of the units in proportion.

5 is a flowchart illustrating a wireless communication method according to an embodiment of the present invention. 1 is a schematic diagram illustrating an advanced general-purpose terrestrial radio access network (E-UTRAN) that is an example of a non-shared baseband network that can be applied to a method according to an embodiment of the present invention; FIG. It is a schematic diagram which shows the example of a different interference cooperation system. It is a schematic diagram which identifies the example of the interference cooperation system which changes with different scenes. It is a time chart which shows the exchange of the signal between a neighbor cell base station and the user device which each of them serves. 1 is a schematic diagram illustrating a wireless communication network divided into a plurality of interference coordination clusters according to an embodiment of the present invention. FIG. 3 is a flowchart illustrating a wireless communication method used in a wireless communication network that can be divided into interference coordination clusters according to an embodiment of the present invention. It is a block diagram which shows the function structure of the radio | wireless communication device by the Example of this invention. It is a block diagram which shows the function structure of the radio | wireless communication device by another Example of this invention.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. It should be noted that, for the sake of clarity, descriptions and descriptions of parts and processes known to those skilled in the art that are not relevant to the present invention are omitted in the accompanying drawings and specification.

  FIG. 1 illustrates a wireless communication method according to an embodiment of the present invention. By using this method, it is possible to control the transmission of ePDCCH or PDSCH in neighboring cells by adopting an optimal interference coordination scheme depending on different scenes.

  In step S101, the edge user device is identified. Specifically, the edge user device can be defined and identified by any method known in the art. For example, there are an identification method based on channel quality information (CQI) feedback, an identification method based on reference signal received power (RSRP), and the like. Below, the identification method by RSRP is demonstrated as an example.

In the identification method based on RSRP, when a threshold value α is set in advance and an RSRP (RSRPserving_cell) of a service cell of the user device and an RSRP (RSRPadjacent_cell) of a neighboring cell satisfy Expression (1), the user device is an edge user device. Is identified.
RSRPserving_cell−RSRPadjacent_cell <α
(1)

  The threshold α can be set based on factors such as the interference resistance capability of the communication system and design needs.

  If the user device is identified as an edge user device, it is determined in step S102 whether there is interference with the ePDCCH of the user device.

  Since the baseband processing center (that is, called a center node or “baseband cloud”) already knows the status of the ePDCCH arrangement of each cell with respect to the shared baseband status between adjacent cells, Need not share ePDCCH arrangement information with each other. In other words, when there is a shared baseband between neighboring cells, the baseband processing center can determine whether there is interference with the ePDCCH of the edge user device.

  In the case of a non-shared baseband, it is necessary to transmit an arrangement sharing signal for sharing ePDCCH arrangement information between adjacent cells to share the ePDCCH arrangement information between adjacent cells. For example, when the network procedure configuration is irregular, for example, a macro cell and a micro cell exist, the ePDCCH arrangement information can be shared by the X2 or S1 interface between the macro cell and the micro cell. A sharing scheme for PDSCH arrangement information between cells is known to those skilled in the art and will not be described in detail here.

  FIG. 2 is a schematic diagram illustrating an advanced universal terrestrial radio access network (E-UTRAN), which is an example of a non-shared baseband network to which a method according to an embodiment of the present invention can be applied. In the example shown in FIG. 2, the ePDCCH arrangement of the user equipment (UE) waiting for scheduling of each base station is shared between the advanced base station (eNB) and the pico base station (Pico) and by the X2 interface of the pico base stations. A configuration sharing signal can be transmitted. The advance base station, the pico base station, and the home base station (HeNB) can each transmit a configuration shared signal that shares the configuration of the ePDCCH with the mobile management device / service gateway (MME / S-GW) through the S1 interface. . Similarly, the home base station and the home base station gateway (HeNB-GW) can transmit an arrangement sharing signal that shares the arrangement of the ePDCCH through the S1 interface.

  Returning to FIG. 1, in the case of non-shared baseband, in step S102, based on the ePDCCH arrangement shared by transmitting the arrangement shared signal between adjacent cells, whether there is interference of the ePDCCH of the edge user device. Confirm. If there is no interference, normal scheduling can be performed. If there is interference, in step S103, in response to the determination that the interference is present, a different interference coordination method is specified for different scenes.

  Specifically, for example, at least one of the following interference coordination methods can be adopted depending on different scenes.

  Method 1, that is, all neighboring cells related to interference transmit ePDCCH.

  Method 2, that is, one of neighboring cells related to interference normally transmits ePDCCH, and another cell releases resources for transmitting ePDCCH or PDSCH.

  Method 3, i.e., one of neighboring cells related to interference normally transmits ePDCCH, and another cell allocates resources for transmitting ePDCCH or PDSCH to user devices in its central region or other sections, and PDSCH One of the ePDCCHs is transmitted.

  FIG. 3 is a schematic diagram showing an example of different interference coordination schemes. FIG. 3 (a) shows an actual example of the interference coordination method of method 1. In this example, mutual interference of ePDCCH occurs between adjacent cells A and B, and adjacent cells A and B related to interference transmit ePDCCH using an orthogonal method. By this method, the adjacent cells A and B can transmit ePDCCH and do not interfere with each other. For example, the ePDCCH transmission of cells A and B can be frequency multiplexed using a bitmap scheme. The example can be basically applied to various wireless communication scenes. For example, the adjacent cells A and B can be applied when the transmission power is the same and are high power transmission cells.

  An example of scheme 1 further includes that cell A and cell B each successfully transmit ePDCCH. This example can generally be realized when cells A and B are the same transmission power and are low power transmission cells.

  FIG. 3B shows an actual example of the interference cooperation method of method 2. In this example, mutual interference of ePDCCH may occur between adjacent cells A and B, and alternatively, the ePDCCH of cell A and the PDSCH of cell B may generate interference. As shown in FIG. 3 (b), cell A normally transmits ePDCCH, and cell B releases resources for transmitting ePDCCH (which may be PDSCH). This example is generally applicable to various wireless communication scenes. For example, the adjacent cells A and B can be applied when the transmission power is different. For example, the ePDCCH is normally transmitted to the cell A with low transmission power, and the resource for transmitting the ePDCCH is released to the cell B with high transmission power.

  (C) of FIG. 3 shows the example of the interference cooperation system of the system 3. In this example, interference between the ePDCCHs occurs between the cells A and B, or interference occurs between the ePDCCH of the cell A and the PDSCH of the cell B. As shown in FIG. 3 (c), cell A normally transmits ePDCCH, and cell B allocates resources for transmitting ePDCCH (or PDSCH) to user devices in its central region or other sections. Then, one of PDSCH and ePDCCH is transmitted. In the example of FIG. 3 (c), the cell B allocates resources for transmitting ePDCCH (or PDSCH) to the user devices in the central area and transmits PDSCH. The third interference coordination method can be applied to various wireless communication scenes. For example, the adjacent cells A and B can be applied when the transmission power is the same and are high power transmission cells.

  Hereinafter, step S103 of the wireless communication method shown in FIG. 1, that is, how to determine different interference coordination schemes depending on different scenes will be described by way of example with reference to a specific embodiment and FIG.

  FIG. 4 is a schematic diagram illustrating an example in which different interference coordination schemes are determined depending on different scenes. Since the transmission priority of ePDCCH is generally higher than the transmission priority of PDSCH, as shown in FIG. 4, first, the occurrence of interference is between ePDCCH transmission or transmission of ePDCCH and PDSCH. (401). When it is determined that interference between the ePDCCH and the PDSCH has occurred, the interference coordination scheme can be selected by a predetermined setting so that the ePDCCH is normally transmitted and the corresponding resource of the PDSCH is released (402, this). Is an example of the above-mentioned cooperation method 2). Optionally, select an interference coordination scheme so that the ePDCCH is transmitted normally and PDSCH or ePDCCH is transmitted by allocating corresponding resources of PDSCH to user devices in the central region or other sections of the cell using the resource. (403, which is an example of cooperative scheme 3 above).

  When it is determined that ePDCCH mutual interference has occurred between adjacent cells, according to one embodiment, an interference coordination scheme can be determined based on the transmission power of the adjacent cells. For example, when adjacent cells have the same transmission power and are low power transmission cells, mutual interference between cells is weak, and therefore, the interference coordination scheme may be set so that any of the adjacent cells can normally transmit ePDCCH. (405, this is an example of one of the above collaboration schemes).

  In another example, when neighboring cells have the same transmission power and are high power transmission cells, the interference between neighboring cells is large, and therefore, ePDCCH transmission between cells is divided in a time division or space division scheme. There is a need. In some embodiments, the interference coordination scheme can be determined to transmit the ePDCCH using an orthogonal scheme in neighboring cells (407, which is an example of the above-described coordination scheme). Specifically, the ePDCCH transmission of the neighboring cell can be frequency multiplexed by a bitmap scheme.

  Alternatively, the interference coordination scheme can be determined so that one of the two high power transmission cells can successfully transmit the ePDCCH and release the corresponding resource of the ePDCCH of another cell (408, which is described above). This is an example of cooperation method 2). In this embodiment, for example, a cell that normally transmits ePDCCH can be specified based on a fair factor of a user device in which ePDCCH interference occurs. More specifically, a cell in which a user device with a higher fairness factor is located can be a cell that normally transmits ePDCCH. The acquisition of the fairness factor of the user device is known to those skilled in the art and will not be described in detail here.

  Optionally, in another embodiment, one of the two high power transmission cells can successfully transmit ePDCCH and the other cell can allocate resources for transmitting ePDCCH to user devices in its central region or other sections. The interference coordination scheme can be determined to distribute and transmit the PDSCH or ePDCCH (408, which is an example of the above-described coordination scheme 3). In this embodiment, for example, a cell that normally transmits ePDCCH can be specified based on a fair factor of a user device in which ePDCCH interference occurs. More specifically, a cell in which a user device with a higher fairness factor is located can be a cell that normally transmits ePDCCH.

  In another example, considering neighboring cell transmit powers are different, the low power transmit cell is generally a hot point or brand point cover, and its ePDCCH transmission priority is set to the ePDCCH of the high power transmit cell. Set higher than the transmission priority. Therefore, the interference coordination scheme is determined so that the ePDCCH of the low power transmission cell is normally transmitted and the corresponding resources of the ePDCCH of the high power transmission cell are released (406, which is an example of the above-described coordination scheme 2).

  Returning to FIG. 1, in response to the determination that ePDCCH interference exists in step S103, different interference coordination schemes are determined for different scenes, and then the process proceeds to step S104. In step S104, transmission of ePDCCH or PDSCH in the neighboring cell is controlled by the determined interference coordination scheme.

  It should be noted that in the case of a shared baseband between neighboring cells, the baseband processing center may interfere based on other information such as ePDCCH location information and cell transmission power of each cell, user device fairness factor, etc. Determine the cooperation method. There is no need to transmit a new signal and report the result of the interference coordination scheme to the base station of an arbitrary cell.

  On the contrary, in the case of the non-shared baseband, the base station that has determined the interference coordination scheme needs to report the final determination result to the adjacent cell of interference. For example, when there are three cooperative schemes, it is possible to define a 2-bit signal and report the determination result of the interference cooperative scheme. For example, when the network procedure configuration is irregular and, for example, a macro cell and a micro cell exist, an interference coordination signal for reporting a confirmation result of the cooperation method is transmitted by the X2 or S1 interface between the macro cell and the micro cell. Can do.

  For the case of non-shared baseband, FIG. 5 is a time chart showing the exchange of signals between neighboring cell base stations BS1, BS2 and user devices (for example, including UE1 and UE2) served by each of them. . As shown in FIG. 5, each user device including user devices UE1 and UE2 calculates the reference signal reception power (RSRP) of its host cell (service cell) and adjacent cell, and the calculated result is shown for each service base station. Feedback to BS1 and BS2. Each of the base stations BS1 and BS2 determines whether or not the user device is an edge user based on the acquired RSRP.

  In addition, the user device provided with UE1 and UE2 further feeds back channel state information (CSI) to the serving base stations BS1 and BS2. Thereby, each of the base stations BS1 and BS2 can identify a user waiting for scheduling based on information such as CSI provided to the user device. Those skilled in the art are familiar with how to identify user devices waiting for scheduling and will not be described in detail here.

  After the user devices waiting for scheduling are identified, the base stations BS1 and BS2 determine whether there is an edge user among the user devices waiting for scheduling. If there is an edge user, the base stations BS1 and BS2 transmit ePDCCH arrangement information of the edge user device among the determined scheduling-waiting user devices through the X2 interface therebetween. In the embodiment shown in FIG. 5, the base station BS1 transmits ePDCCH arrangement information to the base station BS2. Then, the base station BS2 determines an appropriate interference coordination scheme based on the received ePDCCH arrangement information and the ePDCCH arrangement information grasped by itself. After an appropriate interference coordination scheme is determined, the base station BS2 feeds back the determination result to the base station BS1 through the X2 interface. Finally, the base stations BS1 and BS2 perform scheduling for the user device based on the determination result of the interference coordination scheme, and control transmission of ePDCCH and PDSCH.

  Hereinafter, another embodiment of the wireless communication method according to the present disclosure will be described in combination with FIG. 6 and FIG. 7. In this embodiment, the wireless communication network can be divided into a plurality of interference coordination clusters. FIG. 6 is a schematic diagram showing a wireless communication network that can be divided into a plurality of interference coordination clusters according to the present embodiment. In the example shown in FIG. 6, each interference coordination cluster includes a microcell covered by one macrocell and four remote radio heads (RRH). An example of a wireless communication network that can be divided into a plurality of interference coordination clusters is a wireless communication network in which, for example, all base stations in each cluster are connected to a baseband processing center (center node) by optical fibers.

When the wireless communication network is divided into a plurality of interference coordination clusters and each transmission point in the interference coordination cluster shares a baseband, different interference occurs when ePDCCH mutual interference occurs in edge users of adjacent cells in the cluster. Interference coordination between neighboring cells can be performed based on the system throughput T _t in the achievable cluster estimated for the cooperation scheme and the cluster fairness factor P _t . Here, the system throughput (system estimated throughput) T _t in the achievable cluster is defined as the sum of the throughputs of the user devices in the interference coordination cluster, as shown in Equation (2). The cluster fair factor (system fair factor) P _t is defined as the average value of the fair factors of the user devices in the interference coordination cluster, as shown in Equation (3).

Note that p _i and Throughput _i are the fair factor and throughput of user i to be scheduled in the interference coordination cluster, respectively, and n is the number of users to be scheduled.

  FIG. 7 will be described in detail as an example. FIG. 7 is a flowchart illustrating a wireless communication method used in a wireless communication network divided into interference coordination clusters as shown in FIG.

  In step S701, it is determined whether the corresponding user device is an edge user by comparing the RSRP values between the service cell and other cells in the cluster. As the method for defining and determining the edge user, the method described above in conjunction with the equation (1) can be adopted.

In step S702, n scheduling users are specified by a scheduling algorithm. For example, taking the proportional fair algorithm as an example, the fair factor of the user devices in the interference coordination cluster is calculated as in Equation (4).
p _i = r _i / R _i (4)
Note that r _i indicates the throughput of the user i in the current time-frequency resource, and R _i indicates the average throughput of the user i in a certain time zone.

  N user devices to be scheduled are identified based on user fairness factors. If there is an edge user among the n user devices in step S702 and ePDCCH interference occurs in the edge user and other edge users in the interference coordination cluster, the process proceeds to step S703. Otherwise, scheduling is performed according to the scheduling result as it is.

  In step S703, it is determined whether the generated ePDCCH interference is ePDCCH mutual interference or interference between ePDCCH and PDSCH.

  When it is determined that the interference is between the ePDCCH and the PDSCH, in this example, the process proceeds to step S704. In step S704, the interference coordination method is determined so that the ePDCCH is normally transmitted and the corresponding resource of the PDSCH is released. Of course, optionally, the corresponding resources of the PDSCH can also be used for the center user of the cell or users in other sections.

When it is determined that the ePDCCH interference is present, in this example, the process proceeds to step S705. In step S705, the estimated throughput T _t and the interference coordination cluster fair factor P _t are calculated for all the preset interference coordination schemes. The method for calculating the estimated throughput T _t and the interference coordination cluster fair factor P _t is, for example, described in combination with the equations (2) and (3) above.

After the estimated throughput T _t and the interference coordination cluster fair factor P _t are calculated for all the interference coordination schemes, in step S706, the interference coordination scheme is determined by Expression (5).

  Note that v represents the interference cooperation method finally determined. t indicates a predetermined interference coordination scheme, and in this example, there are three types of predetermined interference coordination schemes. Th may be a threshold value selected based on a simulation result.

  As shown in Equation (5), when at least one of the two differences of the cluster fair factors estimated for different interference coordination schemes is larger than the threshold Th, that is, the maximum estimated value and the minimum of the cluster fair factors. When the difference between the estimated values is larger than the threshold value Th, it is determined that the interference coordination method is adopted so that the estimated value of the cluster fairness factor is maximized. A system in an achievable cluster when the maximum difference between two cluster fair factors estimated for different interference coordination schemes, i.e., the difference between the maximum and minimum estimated cluster fair factors is less than or equal to a threshold Th. It is decided to adopt the interference coordination method so that the estimated value of the throughput is maximized.

  The threshold value Th may be set according to an optimal simulation result. When the difference between the maximum estimated value and the minimum estimated value of the cluster fair factor is larger than the threshold Th, the cooperative method corresponding to the cluster fair factor having the maximum value compared to the cooperative method corresponding to the cluster fair factor having the minimum value This means that there are users who have not been scheduled for a long time in, and the resource blocks occupied by these users are always released. In order to ensure the fairness of scheduling, the interference cooperative mode is determined as the target interference cooperative mode. Otherwise, the base station will select the interference coordination mode with the maximum throughput.

  Hereinafter, a wireless communication device that executes the wireless communication method according to the present disclosure will be described with reference to FIGS. 8 and 9.

  FIG. 8 is a block diagram showing a functional configuration of a wireless communication device 800 according to an embodiment of the present invention. The wireless communication device 800 includes an identification unit 810, an interference determination unit 820, and an interference coordination unit 830.

  An identification unit 810 identifies edge user devices. The identification unit 810 executes processing corresponding to step S101 in FIG. For example, the identification unit 810 may compare the edge user device by comparing the RSRP of the serving cell and the neighboring cell.

  Interference determination unit 820 determines the presence of interference on the ePDCCH of the edge user device. The interference determination unit 820 executes processing corresponding to step S102 in FIG. 1 to determine whether ePDCCH interference exists.

  In response to determining the presence of interference, the interference coordination unit 830 determines different interference coordination schemes for different scenes, and controls transmission of ePDCCH or PDSCH of neighboring cells related to interference. In other words, the interference coordination unit 830 executes processing corresponding to steps S103 and S104 in FIG.

  In an example, when interference between ePDCCH and PDSCH occurs in a neighboring cell, the interference coordination unit 830 can release transmission of PDSCH corresponding resources.

  Alternatively, when ePDCCH and PDSCH interference occurs in a neighboring cell, the interference coordination unit 830 allocates PDSCH corresponding resources to user devices in the central region or other sections of the cell using the resources. PDSCH or ePDCCH can also be transmitted.

  In the example, when ePDCCH mutual interference occurs in the neighboring cell, the interference coordination unit 830 can determine the interference coordination scheme based on the transmission power of the neighboring cell. For example, when the neighboring cells have the same transmission power and are both low power transmission cells, the interference coordination unit 830 can cause all neighboring cells to normally transmit ePDCCH. When the neighboring cells have the same transmission power and are both high power transmission cells, the interference coordination unit 830 can cause the neighboring cells to transmit the ePDCCH in an orthogonal manner. For example, the interference coordination unit 830 may perform frequency multiplexing on the ePDCCH transmission of a neighboring cell using a bit mac method.

  In another example, when neighboring cells have the same transmission power and are both high power transmission cells, the interference coordination unit 830 successfully transmits ePDCCH in one of the two high power transmission cells and the other cell. EPDCCH corresponding resources can be released. For example, the interference coordination unit 830 may determine a cell in which the ePDCCH is normally transmitted based on a fair factor of a user device in which ePDCCH interference occurs. More specifically, a cell in which a user device with a higher fairness factor is located can be determined as a cell in which ePDCCH is normally transmitted.

  In another example, when neighboring cells have the same transmission power and are both high power transmission cells, the interference coordination unit 830 successfully transmits one ePDCCH and the other cell transmits ePDCCH. Resources to be distributed to user devices in the central region or other sections so as to transmit PDSCH or ePDCCH. For example, the interference coordination unit 830 may determine a cell in which the ePDCCH is normally transmitted based on a fair factor of a user device in which ePDCCH interference occurs. More specifically, a cell in which a user device with a higher fairness factor is located can be determined as a cell in which ePDCCH is normally transmitted.

  In another example, when the neighboring cell transmission powers are different, the interference coordination unit 830 uses the resources for transmitting the ePDCCH normally in the cell having the lower transmission power among the neighboring cells and transmitting the ePDCCH in the cell having the higher transmission power. Can be released.

  In another example, when the wireless communication network is divided into multiple interference coordination clusters and each transmission point in the cluster shares a baseband, when ePDCCH mutual interference occurs in an edge user of an adjacent cell in the cluster The interference coordination unit 830 can determine the interference coordination scheme between adjacent cells based on the system throughput in the achievable cluster estimated for different interference coordination schemes and the cluster fairness factor. The system throughput in the achievable cluster is defined as the sum of the throughputs of the users in the interference coordination cluster, and the cluster fair factor is defined as the average value of the fair factors of the users in the interference coordination cluster.

  In an example, when the difference between the maximum value and the minimum value of the cluster fair factor estimated for different interference coordination schemes is larger than the threshold, the interference coordination unit 830 has the interference coordination that maximizes the estimated value of the cluster fair factor. It was decided to adopt the method. If the difference between the maximum and minimum cluster fair factors estimated for different interference coordination schemes is less than or equal to the threshold, the interference coordination unit 830 provides interference coordination that maximizes the estimated system throughput in the achievable cluster. It was decided to adopt the method. When the difference between the maximum value and the minimum value of the cluster fair factor is larger than the threshold value, the threshold value corresponds to the cooperation method corresponding to the cluster fair factor having the maximum value compared to the cooperation method corresponding to the cluster fair factor having the minimum value. It is installed to mean that there are users who have not been scheduled for a long time in the scheme.

  Specific examples of the various examples described above have been described in conjunction with the wireless communication method of the present disclosure, and thus are omitted here. In the following, another embodiment of a wireless communication device according to the present disclosure will be described with reference to FIG. FIG. 9 is a block diagram illustrating a functional configuration of a wireless communication device 900 according to another embodiment of the present disclosure.

  The wireless communication device 900 includes an identification unit 910, an interference determination unit 920, an interference coordination unit 930, and an information sharing unit 940. Note that the identification unit 910, the interference determination unit 920, and the interference coordination unit 930 have the same functions and configurations as those of the identification unit 810, the interference determination unit 820, and the interference coordination unit 830 described in conjunction with FIG. Therefore, it will not be described in detail here.

  The information sharing unit 940 can share the arrangement of the ePDCCH by transmitting an arrangement sharing signal between adjacent cells when the baseband is not shared by the adjacent cells that perform interference coordination. In addition, the information sharing unit 940 can report an interference coordination unit determination result by transmitting an interference coordination signal between adjacent cells, for example, via an X2 or S1 interface. For example, when three predetermined interference coordination schemes are included, a 2-bit signal can be used as the interference coordination signal.

  In an example, a wireless communication device according to the present disclosure may employ at least one of the following interference coordination schemes according to different scenes, for example. The examples given above are specific examples of the following three methods. There are the following three interference coordination methods.

  Method 1, that is, all neighboring cells related to interference transmit ePDCCH.

  Method 2, that is, one of neighboring cells related to interference normally transmits ePDCCH, and the other cell releases resources for transmitting ePDCCH or PDSCH.

  Method 3, i.e., one of the neighboring cells related to interference normally transmits ePDCCH, and the other cell allocates resources for transmitting ePDCCH or PDSCH to user devices in its central region or other sections and PDSCH. One of the ePDCCHs is transmitted.

  In an embodiment, the wireless communication device according to the present disclosure may be a base station.

  By using the above wireless communication method and wireless communication device, ePDCCH interference between edge users is reduced, accuracy of edge user reception control information is ensured, and cell edge user frequency spectrum efficiency is improved well, High cell average frequency spectral efficiency is ensured.

  In the above description of specific embodiments of the invention, the features described and / or illustrated for one type of embodiment may be used for one or more other embodiments in a similar or similar manner. It can be combined with the features in this embodiment, or can replace features in other embodiments.

  It should be emphasized that the term “comprising”, as used in this disclosure, means the presence of a feature, element, step or part, but the presence or absence of one or more other features, elements, steps or parts. Do not exclude additions.

  It should be noted that the method of each embodiment of the present invention is not limited to being executed according to the time order described in the specification or shown in the accompanying drawings, and may be executed in parallel or independently according to another time order. good. Accordingly, the order of execution of the methods described herein does not limit the scope of the invention.

Claims (17)

A wireless communication device used in a cooperative multipoint communication system,
An identification unit for identifying an edge user device;
An interference determination unit for determining the presence of interference to the enhanced physical downlink control channel (ePDCCH) of the edge user device;
In response to determining the presence of interference, interference that determines different interference coordination schemes according to different relationships between channels that interfere with each other and controls transmission of ePDCCH or physical downlink shared channel (PDSCH) of neighboring cells related to said interference A coordination unit ,
When said ePDCCH interference to a neighboring cell has occurred, the interference coordination unit, wireless communication devices that determine the interference coordination scheme based on the transmission power of the neighboring cell.   The radio communication device according to claim 1, wherein when interference between ePDCCH and PDSCH occurs in the neighboring cell, the interference coordination unit releases transmission of the corresponding resource of the PDSCH.   When interference between ePDCCH and PDSCH occurs in the neighboring cell, the interference coordination unit allocates the corresponding resource of the PDSCH to user devices in a central area or other sections in the cell using the resource, and the PDSCH or The wireless communication device according to claim 1, wherein the wireless communication device transmits ePDCCH. The wireless communication device according to claim 3 , wherein when the neighboring cells have the same transmission power and are both low power transmission cells, the interference coordination unit normally transmits ePDCCH to any of the neighboring cells. . The wireless communication device according to claim 3 , wherein when the adjacent cells have the same transmission power and are both high power transmission cells, the interference coordination unit transmits the ePDCCH to the adjacent cells in an orthogonal manner. The wireless communication device according to claim 5 , wherein the ePDCCH transmission of the neighboring cell performs frequency multiplexing by a bitmap scheme. When the neighboring cells have the same transmission power and are both high power transmission cells, the interference coordination unit normally transmits ePDCCH to one of the neighboring cells and transmits ePDCCH to the other cell. To distribute user resources in its central area or other sections to transmit PDSCH or ePDCCH,
The interference coordination unit identifies a cell in which ePDCCH is normally transmitted based on a fair factor of a user device in which ePDCCH interference occurs, and ePDCCH is normally transmitted in a cell in which a user device having a higher fair factor is located. The wireless communication device according to claim 1 , wherein the wireless communication device is specified as a cell. When the neighboring cells have different transmission powers, the interference coordination unit normally transmits ePDCCH to a cell having a lower transmission power among the neighboring cells and releases resources for transmitting the ePDCCH to a cell having a higher transmission power. The wireless communication device according to claim 1 . If the base band is not shared in the adjacent cell for interference coordination, further comprising information sharing unit that shares the arrangement of ePDCCH by transmitting arrangement shared signals between adjacent cells, claim 1-8 The wireless communication device according to one. The wireless communication device according to claim 9 , wherein the information sharing unit transmits an interference coordination signal between adjacent cells and reports a determination result of the interference coordination unit.   When a radio communication network is divided into a plurality of interference coordination clusters and a baseband is shared by each transmission point in the interference coordination cluster, ePDCCH mutual interference occurs in an edge user of an adjacent cell in the interference coordination cluster The interference coordination unit determines an interference coordination scheme between the adjacent cells based on a system throughput and a cluster fair factor in the achievable cluster estimated for different interference coordination schemes. 2. The wireless communication according to claim 1, wherein the system throughput is defined as a sum of throughputs of users in the interference coordination cluster, and the cluster fairness factor is defined as an average value of user fairness factors in the interference coordination cluster. device.   When ePDCCH mutual interference occurs in the neighboring cell, the interference coordination scheme is one in which the neighboring cells transmit ePDCCH, and one of the neighboring cells normally transmits ePDCCH, and the other Method 2 in which a cell releases resources for transmitting ePDCCH or PDSCH, and a central area for resources in which one of the neighboring cells normally transmits ePDCCH and the other cell transmits ePDCCH or PDSCH. 2. The wireless communication device according to claim 1, comprising at least one of scheme 3 for transmitting either PDSCH or ePDCCH allocated to user devices in another section. A wireless communication method used in a cooperative multipoint communication system,
Identify edge user devices,
Determining the presence of interference to the enhanced physical downlink control channel (ePDCCH) of the edge user device;
In response to determining the presence of the interference, different interference coordination schemes are determined according to different relationships between channels that interfere with each other, and transmission of an ePDCCH or a physical downlink shared channel (PDSCH) of an adjacent cell related to the interference is performed. control and,
A radio communication method including determining the interference coordination scheme based on transmission power of the neighboring cell when ePDCCH mutual interference occurs in the neighboring cell . Wherein when the neighbor cell interference ePDCCH and PDSCH occurs, it releases the transmission of the corresponding resources of the PDSCH, the radio communication method according to claim 1 3. When interference between the ePDCCH and the PDSCH occurs in the adjacent cell, the PDSCH corresponding resource is allocated to user devices in the central region or other sections in the cell using the resource, and the PDSCH or the ePDCCH is transmitted. the wireless communication method according to claim 1 3. A computer storage medium comprising computer-readable commands, the computer-readable commands, a computer storage medium for executing the method according to any one of claims 1 3 to 1 5 to the computer. An apparatus in a wireless communication system, and at least one memory storing computer commands, said by executing the computer commands stored in at least one memory to claim 1 3 to 1 5 An apparatus comprising a processor for performing the described method.

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